Generally, a magnetic recording medium is produced by painting a magnetic powder composition comprising magnetic powder and a binder on a substrate film surface or by metallizing the surface with a ferromagnetic metal or its alloy to form a magnetic layer. Since the magnetic layer is vigorously slid on a magnetic head during recording and reproducing, the magnetic layer is heavily abraded. Thus, it is highly desired to provide a magnetic layer which is less abraded so that the durability of the magnetic recording medium is prolonged.
To impart good durability to the magnetic recording medium, it was proposed to cover the surface of the magnetic layer with various lubricants. Among the lubricants which may be used, having a perfluoroalkyl group are known to be highly effective. Further, in order to improve the adhesive property of the lubricant to the magnetic layer, it was proposed to use, as a lubricant, a compound having a terminal polar group (e.g. a carboxyl group and its salt form) in addition to a perfluoroalkyl group (cf. Japanese Patent Kokai Publication (unexamined) Nos. 152543/1982 and 200939/1982). It was also proposed to use a perfluoroalkyl carboxylic acid to which HO(CH.sub.2 CH.sub.2 O).sub.n H is added as a lubricant to improve both solubility and lubricity (cf. Japanese Patent Kokai Publication (unexamined) No. 45456/1979).
However, the compound having the perfluoroalkyl group and the terminal polar group is dissolved only in a fluorine-containing solvent. Further, since the perfluoroalkyl group is comparatively rigid, the coefficient of friction of the surface is not sufficiently decreased and the abrasion resistance of the magnetic layer is not improved as expected although the surface is fluorinated. The perfluoroalkyl carboxylic acid added with HO(CH.sub.2 CH.sub.2 O).sub.n H can overcome the drawbacks of the compound having the perfluoroalkyl group and the terminal polar group and improve the solubility and lubricity. But, since it has a polar alcoholic hydroxyl group, its adhesive property to the magnetic layer is still insufficient so that the improvement in abrasion resistance is not satisfactory.